Methods for Preparing Oat Bran Enriched in Beta-Glucan and Oat Products Prepared Therefrom

ABSTRACT

Dry milling methods for preparing oat products enriched in the content of β-glucan and methods for preparing foodstuffs incorporating such an enriched oat product especially ready-to-eat cereals are provided. Heat conditioned dehulled oats are dry milled to form a coarse whole non defatted oat flour and then, without a preceding removal of fat, dry fractionated into coarser bran and finer oat flour fractions at multiple stages. The coarse oat flour is first dry classified to separate or form a coarser fraction oat bran containing more concentrated β-glucan and a finer oat flour or starch containing or endosperm containing fraction. The oat bran is subjected to second and third rounds of milling and classification to form a high β-glucan content (&gt;7-9%) oat bran and a low β-glucan content (3%) oat flour. The oat bran and oat flours can be used to prepare foodstuffs such as ready-to-eat cereals.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application represents a divisional application of U.S.patent application Ser. No. 10/756,063 entitled Method for Preparing OatBran Enriched in Beta-Glucan and Oat Products Prepared Therefrom” filedJan. 13, 2004, pending.

BACKGROUND OF THE INVENTION

The present invention relates to food product processing, such as themilling of oats to provide milled oat products such as oat bran and oatflour. More particularly, the present invention is directed towards animproved process for milling oats to provide for oat bran high inβ-glucan and to β-glucan enriched whole grain oat flour comprising theenriched oat bran and to low fiber oat flour.

Cereal grain seeds generally contain a small amount of beta-glucan, withoats and barley being recognized as the richest sources of thismaterial. The naked oat seed, known in the art as a “groat”, typicallycontains 2-4% by weight β-glucan, depending upon oat variety and otherfactors such as growing conditions. Barley seeds can typically containtwice as much beta-glucan as groats. Beta-glucan is generally found inhigher concentrations in the outermost layers of the seed (i.e., the“bran”). Thus, oat bran contains generally a minimum of 5.5% by weightbeta-glucan, and typically contains up to 6% up to less than 7% byweight beta-glucan.

The present invention resides in methods for preparing an oat branhaving higher levels of β-glucan content, i.e., higher than about 7%.

Oatmeal and oat bran are popular hot cereal consumer products. Oat basedReady-To-Eat (“RTE”) cereal or cold cereal are also popular consumerfoods packaged food products. One popular line of oat based RTE cerealproducts is available in puffed “O” shaped pieces fabricated from acooked cereal dough comprising whole grain oat flour. Other RTEoat-based products are available in the forms of flakes as well as inthe form of biscuits or even other puffed shapes.

Improvements in oat processing are known to provide oat flours ofimproved flavor and stability (see, for example, U.S. Pat. No. 5,523,109“Oat Flour And Method Of Preparation” issued Jun. 4, 1996 to Hellweg, etal.). In the methods of '109 patent, whole oat groats are steamed forgreater times than was then conventional, dry toasted for extended timesand milled to provide the improved flavor conditioned oat flour. Theimproved oat flour can then be used to prepare puffed oat based RTEcereal products especially puffed “O” shaped products. However, the '109patent does not teach or suggest fractionation of the oat flour soproduced or that any benefit would be derived there from.

Such oat based products are popular not only for their taste and textureeating qualities but also because of the nutritional properties of theoats from which these products are prepared. In addition to high levelsof protein provided by oats, are known as a good source of solublefiber. A good description of the literature pertaining to the healthdiscussion on the role of fiber is found in U.S. Pat. No. 4,777,045(issued Oct. 11, 1988 to Vanderveer et al. and is entitled High BranSnack) which is incorporated herein by reference.

There is a growing awareness of the health benefits to people associatedwith soluble fiber consumption, especially reductions in blood serumcholesterol, i.e., antihypercholesterolemic benefits. Total dietaryfiber (“TDF”) comprises both soluble dietary fiber (“SDF”) and insolubledietary fiber (“IDF”). In addition to insoluble fiber, oat and barleywhole grain cereal flours contain soluble fiber which predominantlycomprise β-glucans.

Thus, whole grain oat flour based RTE cereals are naturally andbeneficially high in β-glucan fiber levels due to native 2-4% levels ofβ-glucan in whole grain oat flour. However, for even better fibernutrition, it would be desirable to fortify oat based RTE cereals withβ-glucan. Since β-glucan is higher in concentration in oat bran (5.5% tounder 7%), the cereal products can be formulated with added levels ofoat bran. However, as the concentration of oat bran increases in suchproducts (beneficially increasing the β-glucan content) other propertiessuch as cost increases and puffability correspondingly decrease.

One approach is to fortify oat based RTE cereal formulations with oatbran ingredients that are selectively higher in β-glucan content. Whilesuch products are known and are commercially available (such as fromCan-Oat Milling, a wholly owned subsidiary of Saskatchewan Wheat Pool,Portage La Prairie, Manitoba, Canada R1N 3W1), such high β-glucan oatbran products are high in price and are produced by methods that areproprietary. Also, while such products are higher in β-glucan content,such products do not have the improved flavor profile of the oat flourproducts prepared by the methods of the Hellweg '109 patent. Morerecently, methods for producing oat products high in β-glucan have beendescribed in published US patent application US 2003/0087019 A 1published May 8, 2003.

Barley also contains beta glucan. While most barley varieties are bredfor low β-glucan content (since β-glucan is inimical to brewing clearbeer), some barley varieties are high in β-glucan content. Dry millingmethods for preparing a β-glucan rich material from barley are alsoknown and for the provision of RTE cereals prepared there from (see forexample, U.S. Pat. No. 5,151,283 “High Soluble Fiber Barley ExpandedCereal and method of Preparation” (issued Sep. 29, 1992 to Foehse etal.). However, the '283 patent teaches that due to the differencesbetween barley and oats, teachings regarding processing of one grain arenot transferable between oats and barley. Indeed, commercial millingoperations are typically designed and operated to process single graintypes. Also, when providing whole grain oat products especially popularpuffed RTE products, addition of barley based ingredients can be seenundesirably diluting the oat identity of such products.

Wet extraction methods for preparing β-glucan from oat flours are known(see for example U.S. Pat. No. 6,323,338 “Method for concentratingB-glucan” issued Nov. 27, 2001 to Potter, et al.). The '338 patentteaches that “Previous processes for concentrating beta-glucan fromcereals such as oats or barley have proven impractical for commercialmanufacturing processes because of high cost and/or low yields.”Notwithstanding described improvements, commercial wet extractionβ-glucan methods remain uneconomical for mass produced consumer foodproducts.

Thus, in view of the present state of the art, there is a continuingneed for methods for preparing a high β-glucan content oat braningredient. There is also a continuing need for less expensive β-glucanextraction techniques compared to known wet extraction methods.

There is also a need for whole grain oat flours enriched with highlevels of β-glucan that provide the taste and cook properties of knownwhole grain oat flours of lower oat bran and β-glucan contents.

There is also a continuing need for the methods of preparing highquality fine oat flour characterized by low levels of bran and betaglucan content for the preparation of oat based RTE cereals of highpuffability and low density.

Surprisingly, methods have now been discovered that satisfy these needs.These methods involve dry milling fractionation methods that can beconveniently practiced using known milling equipment and systems incommercial oat milling facilities.

SUMMARY OF THE INVENTION

In its method aspect, the present invention resides in dry millingfractionation methods. The methods involve processing oats to form abran fraction and oat flour fraction, comprising the steps:

-   -   bolting (20) coarse whole heat conditioned grain oat flour (19)        having a native β-glucan content to form a first coarser major        first pass β-glucan rich oat bran fraction (21) having a        particle of greater than 600 μm and a second finer minor first        pass low bran oat flour (22) having a particle size of less than        600 μm; flaking (24) the first pass oat bran fraction to form        flaked oat bran (25);    -   bolting (26) the flaked first pass oat bran to form a first        coarser major second pass β-glucan rich oat bran fraction (28)        having a particle of greater than 600 μm and a second finer        minor second pass low bran oat flour (22) having a particle size        of less than 600 μm;    -   dry milling (30) the major second pass β-glucan rich oat bran        fraction (28) to form a milled oat bran (31); and,    -   bolting (32) the milled oat bran (31) to form a first coarser        major third pass β-glucan rich oat bran fraction (50) having a        particle of greater than 300 μm and a second finer minor third        pass low bran oat flour (33) having a particle size of less than        300 μm.

In its principle product aspect, the present invention provides highβ-glucan content oat bran as well as improved flavor and cookability.The oat bran is characterized by a in β-glucan content of at least 7%.The oat bran has an improved flavor profile that can be expressed bysyringic to ferulic ratio of at least 2.5:1. The product is partiallyheat processed as expressed in a Farinograph cook value ranging fromabout 5-20 minutes. The oat bran fraction has a β-glucan content atleast twice that of the oat flour from which the bran is fractionated.

In other product aspect, the present invention provides a low bran oatflour. The low bran oat flour has a β-glucan content of less than 3%.The low bran oat flour has an improved flavor profile that can beexpressed by syringic to ferulic ration of at least 2.5:1. The low branoat flour product is partially heat processed as expressed in aFarinograph cook value ranging from about 5-20 minutes.

In still another product aspect, the present invention resides in wholeoat flours fortified with added amounts of the present high β-glucancontent oat bran to provide a high β-glucan content oat flour and havingimproved flavor and cook characteristics.

In still another product aspect of one and the same invention, thepresent invention resides in ready-to-eat products high β-glucan oatbased cereal that find particular appeal to health conscious consumers.

In still another aspect of one and the same invention, the presentinvention resides in ready-to-eat low β-glucan oat based cereal productsthat find particular appeal to children.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a highly schematic representation of a method for processingoat groats into high β-glucan oat bran and into a low bran oat flour inone embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed towards improved processes for millingoats to provide an oat bran high in β-glucan; a β-glucan enriched wholegrain oat flour comprising the enriched oat bran; and to a low brancontent oat flour.

Throughout the specification and claims, percentages are by weight andtemperatures in degrees Centigrade (° C.) unless otherwise indicated.Each of the US patent's and applications reference herein are herebyincorporated by reference.

Referring now to FIG. 1, there is depicted a flow diagram of a processfor preparing an improved milled oat materials generally designated byreference numeral 10. Oats are received in bulk such as from railroadcars and dehulled to provide dehulled oats or oat groats 12. The oatgroats 12 generally will have an initial moisture content ranging fromabout 8 to 10%. The oat groats 12 are cleaned in cleaning step 14 toprovide cleaned oat groats 15 to remove residue such as dirt, smallstones, undersized corns and residual hull fragments. The oat groatswill have an initial native β-glucan content ranging from about XXX toXXX % depending upon such factors as variety, crop years, etc. Thecleaned oat groats 15 are then heat conditioned 16 with steam 13 toprovide cleaned conditioned to groats 17. In one embodiment, the heatconditioning step 16A is generally practiced to inactivate enzymes toprovide a enzyme inactivated or conditioned oat groats. The steaminjection conditioning step 16A is designed primarily to inactivate theenzymes including lipase, lipoxigenase, peroxidase, amylase, andprotease. The conditioned oat groats will have a negative peroxidaseactivity as measured by AAAC test method 963.27 (American Association ofCereal Chemists, 15th Ed., 1990). Conventional treatment methods,including times and temperatures, can be used to practice the heatingstep. Generally, the step involves heating for about 10 to 15 minutesusing steam at about 5 to 20 psig (120 to 150 KPa). The steamed oatgroats have a moisture content increased to about 16 to 25% by virtue ofmoisture absorption from the steaming exposure step.

However, in a preferred embodiment, the oat groats can be treated by theextensive heat treatment methods 16B for flavor development and asdescribed in my U.S. Pat. No. 5,523,109 patent to provide conditionedoat groats 17B characterized not only low levels of residual enzymeactivity but also by improved flavor and improved cook characteristics.The improved flavor attribute can be expressed by and the oat groats 17Bhave a ratio of syringic acid to ferulic acid being greater than orequal to 2.5. The improved cook characteristics can be expressed by andthe oat groats 17B can have a Farinograph value of about 5-20 minutes,preferably about 6 to 14 minutes.

In this particular preferred embodiment, the present methods cancomprise the step of dry heating the steamed oat groats 16B such as byindirect steam contact to 185° to 230° F. (85° to 110° C.) in anappropriate vessel such as in toaster for about 70 to 10 minutes toprovide a conditioned and toasted oat groats 17B. By virtue of theextended heat treatment, the oat groat 17B moisture content is reducedand can range from about 9 to 14%. The steamed, enzyme deactivated oatgroats 17B are heated to provide improved cook characteristics thatlessen the energy requirements for cooked dough development and todevelop a cooked flavor in the groats. Sufficient extended heattreatment is indicated when the oat groats 17B express a Farinographcook time value of about 5 to 20 minutes. Within this range, for thoseflours to be used in cooker extruders such as a twin screw extruderbetter results in terms of reductions in needed duration of subsequentcook times is obtained when the Farinograph cook time value ranges fromabout five to eight minutes, while for extended cook time cookers,better results are obtained when the Farinograph cook time ranges fromabout 14 to 20 minutes.

A Farinograph measurement is a standard test method by the AmericanAssociation of Cereal Chemists: AACC test method 54-21. The present cookor development time is a modification of the AACC test except that 1)the oat flour herein is used in substitution for wheat flour, and 2) thestart point is developed at 95° C. rather than room temperature.Generally, a Farinograph is used to measure the torque required to mixoat flour dough at heated temperature. The time needed to developmaximum torque indicates the level of energy input required to form acohesive dough. A shorter dough development or cook time in theFarinograph is indicative of a higher level of steam pretreatment.

In certain preferred embodiments (not depicted), the dry heating ortoasting step 16B can include a first sub step of venting the steam toform steamed and vented oat groats. The venting reduces the moisturecontent to about 15 to 20%. Thereafter, the dry heating step can includea second sub step of dry heating the steamed and vented oat groats toform the steamed and toasted oat groats. The step can be practicedemploying indirect steam or other dry heating technique. The dry heatingtechnique can be continued to yield the finished conditioned oat groathaving a moisture content of about 9 to 14%. The skilled artisan willappreciate that the process can be practiced employing multiple vesselsor a single vessel (e.g., gravity fed) having multiple sections orchambers.

Dry heating as used herein means heating only in the presence of anymoisture which may be inherently present in the oat groats as a resultof the prior steaming step but not in the presence of any additional oradded moisture nor in the presence of a humid atmosphere, i.e., >40%relative humidity.

The preferred finished steamed and toasted oat groats 17B result in acooked cereal flavor in the resulting flour. The oat groats and floursprepared therefrom can be characterized syringic ferulic by a ratio ofspecific phenolic acids that indicate improved flavor. Morespecifically, the oat groats and flours prepared therefrom can have asyringic to ferulic acid content ratio that is higher in syringic acid.The ratio of syringic acid to ferulic acid can range from about 2.5:1 upto 5.5:1. In preferred embodiments, the ratio is at least 3:1. Oneanalytical method utilized to act as a marker for this flavordevelopment is the HPLC (high performance liquid chromatography) arearatio of specific phenolic acids of >2.5. Specifically, the numerator isHPLC area for the syringic acid peak combined, and the denominator isferulic acid peak area determined by HPLC retention times. The numeratorarea corresponds to concentration and has to this point been observed torange from about 10 to 35 ppm and the denominator will range from about4 to 7 ppm. The syringic acid peak (including its associated phenolicester having an HPLC elution time of 0.7 minutes differential) has beenobserved to be positively correlated with increased heat treatment ofthe oat groats while the ferulic acid level remains fairly level. Thus,increased heat treatment or toasting results in greater flavordevelopment and in a greater amount of phenolic ester and a larger ratiovalue.

The dry heating step 16 will continue to gelatinize the starch, but theprimary function of the heating process is to toast the oat groat togenerate a distinct toasted flavor. The toasted flavor in the oat flourwill impart desirable flavor to the extruded cereal products. To ensureproper toasting, the moisture content and heated temperature of the oatgroats, as well as the heating time play important factors. In general,the moisture content of the oat groats entering the heating zone (afterventing) should be in the range of 15 to 20%. The heating temperature ofthe oat groats should be in the range of 185 to 230° F. The heating timeis in the range of 70 to 110 minutes or longer.

In the '109 patent the conditioned oat groats were milled directly toprovide a whole oat flour having an improved flavor and desirablecooking attributes. No effort was made to fractionate the milled graininto separate bran and flour fractions.

The cleaned conditioned oat groats 17, especially those of enhancedflavor 17B prepared by the methods of the' 109 patent, are the startingmaterial for the present process 10. The present methods comprise thestep of milling 18 the cleaned and conditioned oat groats 17 to providecoarse non-defatted whole (or, equivalently, “whole grain, i.e.,containing both flour and bran) oat flour 19. For convenience ofunderstanding relative material flows, the process flow diagram FIG. 1assumes a starting quantity of oat groats 17 (whether 17A and/or 17B) of100 kg. and that all 100 kg is milled to form oat flour 19.

Conventional milling equipment and can be used to practice milling step18. For example, a Buhler “X” mill (A small scale mill often used forflour and grain milling development purposes) can be used to practicethis step on a bench-top or development scale. In a preferredembodiment, milling step 18 is practiced on a commercial or industrialscale such as using an impact mill or a milling roll stand, i.e., a pairof counter rotating milling rolls. The milling roll stand can beoperated with the two rolls operating at differential speeds rangingfrom about 1:1 to about 3:1, preferably about 2:1. In this preferredvariation, one roll is operated at about 60 revolutions per minute(“RPM”) while the second is operated at about 30 RPM. The roles are setat a nip gap of about 15 to 45 mil or (0.015 to 0.045 inch; i.e., about380 to about 1150 micrometers), preferably about and 25 to 35 mils (640to about 880 micrometers). In commercial operations, in preferred form,4 inch (10-11 cm) diameter milling rolls can be used having variousmilling roll corrugations. The skilled artisan will have no difficultyin selecting useful milling roll configurations. In even more preferredform, one roll is provided with a “Dawson 25” pattern (i.e., having aDawson pattern at 25 corrugations per inch) with a 0.25 inch axial twist(i.e., 0.25 inches of twist per 12 inch of extension). In thisvariation, the second milling role is provided with a “Minneapolis 19”style or 22 corrugation cuts per inch also with a 0.25 inch axial twist[A better description of milling industry standard types of milling rolecorrugations such as “Dawson” and “Minneapolis” can be through CreasonCorrugating Co. (4110 South Creek Road, Chattanooga, Tenn. 37406 USA)].

The whole grain oat flour 19 has its native level of β-glucan typicallyranging from about 2-4%. In other variations, varieties of oats havinghigher native levels of β-glucan can also be used and, less preferably,varieties having lower levels of β-glucan. For example, certainspecialty varieties of oats are now available having up to 8% β-glucanand can be used herein. If and when commercial quantities of such oatmaterials are available at sensible pricing, then such startingmaterials of such oat varieties will be highly suitable for use in thepresent methods. Also, it is contemplated hereon that future varietiesof oats having even higher native levels of β-glucan will be developedin the future that can be usefully processed according to the presentmethods to produce the various oat products of the present invention andare thus contemplated for use herein.

The present methods can further comprise a first bolting or fractioning(i.e., separating into fractions based upon size) step 20 to separatethe coarse oat flour 19 into a first pass oat bran fraction 21 and afirst pass low bran oat flour 22. The bolting step 20 can be practicedby size selection such as by passing or screening the whole four througha US standard size 34 sized sieve or screen. The first pass oat brandfaction 21 will be larger both in size and amount. For example, for aplant processing coarse oat flour 19 at a rate of 100 kg/hr, the oatbran fraction 21 will typically range about 52 to 58 kg/hr, and forconvenience depicted in FIG. 1 as about 55 kg/hr. The larger oat branparticles will be retained on the US standard size 34 screen (i.e., arelarger than about 600 micron). Particles smaller than about 600 micronpass through the size 34 screen at a rate of about 42-48 kg thatcomprise the low bran (and thus low β-glucan content) oar flour 22. Thefirst pass low bran oat flour 22 generally will have low levels of oatbran and thus low levels of β-glucan, typically less than 3% and oftenmuch less, e.g., less than 1%. While preferred for use herein is a No.34 US standard size screen, the skilled artisan will appreciate thatvariations in screen size selection can be made without departing fromthe invention so long as a dry separation is made between the relativelylarger bran particles (i.e., those particles larger than about 0.600 mm,i.e., 600 micrometers) and those small particles that comprise thestarchy endosperm oat flour fraction. For example, a screen size can beselected (or other size separation technique) that fractions the oatflour into a fraction larger than 500 microns and smaller than 500microns. Likewise, the screen can be selected to fraction the flour intoa fraction having a size larger than 700 microns and a fraction smallerthan 700 microns. However, selection of such screen sizing can influenceboth the yield and concentration of the desirable high beta glucan endproduct of the present invention.

If desired, such as for commercial efficiency, the first bolting step 20can be practiced employing one or more sub-steps (not shown). Forexample, the oat flour 19 can be initially passed through a first screenhaving larger sized openings, e.g., a US standard size No 18 screen. Acoarser first pass oat bran fraction is retained upon the No 18 screen.The oat material that passes through the No 18 screen (about 1 mm orsmaller) is then passed through the No. 34 sized sieve to provide a fineor finer first pass oat bran fraction and the first pass low bran oatflour 22. Thereafter, the coarser first pass oat bran fraction (that isretained upon the No 18 screen and thus is larger than about 1 mm) iscombined with the finer first pass oat bran fraction to provide thefirst pass oat bran 21 material or sub-stream.

Of course, different milling facilities can use different millingequipment such as differently sized screens. However, in each variationa more coarse oat bran fraction is obtained that is selectivelyconcentrated in the β-glucan constituent. Generally, the fractionationstep is practiced to provide an oat bran fraction 21 having its β-glucanconcentration increased on the order of about 2% above its native orstarting level. Thus, a coarse whole oat flour stream or material isfractionated into an oat bran fraction 21 having about 5% orsubstantially all of the β-glucan constituent and a second smaller oatflour fraction 22 containing a reduced β-glucan content (typically under2% assuming a starting concentration of about 3% in the oat flour 19)and relatively more of the starchy endosperm fraction. Of course, theparticular β-glucan content in the fractions 21 and 22 will depend uponthe starting concentration such factors as oat variety as well asyear-to-year crop variations.

The present oat milling methods 10 can further comprise an oat bran sizereducing step 24 such as a flaking step wherein the first pass oat branfraction 21 is flaked to provide a size reduced or flaked oat bran 25.The flaking step 24 can be practiced conveniently such as by passing thefirst pass oat bran fraction 21 through a pair of counter rotatingdouble roll stand or flaking rolls. In preferred form, the flaking rollsare set at a nip gap setting of up to 20 mils (0.020 inch, or,equivalently, ˜500 micrometer or “μm”). In the flaking double rollstand, each roller is preferably a smooth roll. As in milling step 18,the rolls can be counter rotated at differential roll speeds rangingfrom about 1:1 to about 3:1 and at speeds ranging from about 20 to 100RPM. In a preferred embodiment, one roll is operated at about 60 RPMwhile the second is operated at about 30 RPM to provide a differentialroll speed of about 2:1.

The present methods can further comprise a second bolting orfractionation step 26. The flaked oat bran 25 is separated orfractionated in the second bolting step 26 into a larger quantity orfraction of a second pass oat ban fraction 28 and a smaller quantity orfraction low bran oat flour 27. In a manner similar as described abovefor step 20, the second bolting step can be practiced by passing theflaked oat bran 25 through a screen or sieve such as a US Standard sizeNo 34 screen. The larger sized oat bran 28 is retained upon the No 34screen while the smaller sized (and amount) second pass oat flour 27passes through the No 34 screen to form the second pass low bran oatflour 27. In commercial practice, the 55 kg/hr stream of flaked oat bran25 is separated into a sub-stream of about 45 (42-48) kg/hr of secondpass oat bran 28 and the balance, about 10 (plus or minus 3) kg/hr, ofsecond pass low bran oat flour 27. Substantially all of the β-glucan isassociated with the oat bran 28 and the second pass oat flour 27generally will have p-glucan levels of less than 2.5%. It will beappreciated that less oat flour is extracted or separated in the secondbolting step 26 than in the first bolting step 20 since the flaked oatbran 25 is more concentrated in the bran fraction and contains less ofthe starchy oat flour than the coarse oat flour 19. The second pass lowbran oat flour 27 is collected as a separate sub-stream and/or can becombined with the first pass low bran oat flour 22 sub stream.

The second pass oat bran 28 material generally comprises about 6% to 7%β-glucan and more preferably about 6.5% β-glucan. That is, oat bran 28has a β-glucan concentration about twice that of starting material oatflour 19 or, otherwise expressed, has a β-glucan beneficiation ratio ofat least 2.0. In more preferred embodiments, oat bran 28 has a β-glucanconcentration at lest 2.3 times greater than starting material oat flour19. For certain applications, oat bran 28 can be used as a high β-glucancontent ingredient per se. In other variations, oat bran 28 is anintermediate product useful for further processing (as describedimmediately below) for to prepare an oat fraction even more highlyconcentrated in β-glucan. In certain preferred embodiments wherein thehigh flavor oat groats are selected to provide the starting oat flour19, the oat bran fraction 28 also exhibits the desirable improved flavorprofile that can be expressed by a syringic to ferulic ration of atleast 2.5:1. Also, oat bran fraction 28 can have improved cookattributes expressed as having a Farinograph value of between 5 and 20minutes, preferably about 6 to 14 minutes. For example, oat branfraction 28 can be used as the principle ingredient in a hot oat brancereal. If desired, the oat bran can be admixed with small quantities ofsalt, flavorings, sweeteners and/or dried fruit pieces to provide a drymix for a hot oat bran cereal.

The second pass oat bran 28 can be fed into and the present methods cancomprise a milling 30 step to provide a milled oat bran 31. It will beappreciated that milling step 30 is the third milling step that sizereduces the oat particles and the second that size reduces only the oatbran. In a preferred variation, milling step 30 is practiced employing ahammer mill. A hammer mill is a common milling equipment item. While notwishing to be bound by the proposed theory, it is speculated herein thatthe β-glucan is bound with the bran so tightly that by breaking the allbran up such as with a hammer mill, the β-glucan constituent is releasedfrom the oat bran or at least made more available to measurement.Additionally, hammer milling the second pass oat bran 28 beats orreleases more endosperm from the oat bran 28 allowing for completeseparation of the starchy endosperm from the bran in the to-be describedstep 32. In preferred form, conventional hammer mills are employed topractice the milling step 30. In more preferred form, the hammer mill isequipped with a #6 US standard size sieve exit screen through which themilled oat bran 31 must pass to provide a milled oat bran 31 having aparticle size of >3 mm. Milled oat bran 31 generally comprises about 6%to 7% β-glucan.

It has been surprisingly found that the ambient humidity can affect theresults of the hammer milling step 30 and the extraction efficiency ofthe to be described third bolting step 32. While not wishing again to bebound by the proposed theory, it is speculated that higher environmentalhumidity conditions increase the dew point. At higher dew point's, lessmoisture is lost from the oat bran caused by the heat generated duringthe hammer milling step 30. As the milled oat bran 31 is conveyed to thethird bolting step 30, moisture flashes off in proportion to the dewpoint of conveying air. Less moisture loss results in tougher oat branwhich in turn can results in less bran loss to the flour extracted andthe third bolting step 30 to in turn less bran loss to the oat flour inbolting step 30 to results in increased bran extraction and thus higherconcentrations of β-glucan in the bran fraction. Thus, greaterextraction rates of high about 6% to 7% β-glucan oat bran can beexpected under higher ambient moisture conditions due to such factors asweather, season and geographic location.

The present methods 10 can comprise a third bolting or fractionationstep 32 wherein the milled oat bran 31 is fractionated to form a firstminor third pass low bran oat flour 33 comprising the smaller or fineroat flour particles and a second fraction of the comprising the largersized high β-glucan oat bran fraction 50. In preferred form, the thirdbolting step 32 to is practiced in a manner similar to the practice offirst bolting step 20 and second bolting step 26. More specifically, inpreferred form, the third bolting step 32 is practiced by a sizeclassification of the relatively larger all bran particles from therelatively smaller third pass low bran oat flour 33. Similar equipmentand techniques can be used to practice the third bolting step 32 to thatpracticed in the first bolting step 20 and/or the second bolting step26. The milled oat bran 31, for example, can be pass through a finerscreen than used in steps 20 or 26 screen such as a US standard size No.50 screen or finer to separate the relatively larger high p-glucan allbran fraction 50 that is retained upon the screen allowing to passthrough this green the smaller sized oat flour 33 particles. As aresult, the oat flour 33 generally will have a particle size of lessthan 300 μm and β-glucan of less than 3% while the oat bran 50 separatedwill have a particle size greater than 300 μm.

The third pass low bran oat flour 33 material or sub stream can becollected or, in preferred form, combined with the first pass low branoat flour 22 as well as the second pass low bran oat flour 27 to form alow bran oat flour product designated by reference numeral 40. While notcritical per se, the oat flour 33 extraction is effective to removeabout 10 kg per 100 kg of oat flour 19 starting material or 10 kg/hourfrom the 45 kg per hour feed stream milled oat bran 31 to the thirdbolting step 32. When the third pass low bran oat flour 33 is combinedwith the earlier formed oat flour fractions 22 and 27, about 60 to 70 kgper 100 kg of starting oat flour of a low bran oat flour 40 isextracted, preferably about 65 kg. The balance retained on the screenfrom the third bolting step 32 is relatively high in β-glucan content.The β-glucan content of the high β-glucan oat bran fraction 50 can rangefrom about 8 to 9%, and more typically about 8.5% depending upon suchfactors as the ambient humidity associated with location and time ofyear.

The low bran oat flour 40 so prepared is useful as an ingredient in thepreparation of a variety of oat based consumer products especiallyconsumer food products. The low bran oat flour 40 is particularly suitedfor use in connection with the preparation of cooked oat based puffedready eat cereals. In particular, the low bran oat flour 40 isparticularly suitable for use for the production of puffed oat based RTEcereals for children. Such products can be more highly puffed to lowerdensities relative to those obtained from whole oat flours and withoutthe addition of diluent starches and, by virtue of the absence or lowlevels of the oat bran constituent, are beneficially characterized bylower levels of strong or bitter oat taste. Some consumers, especiallychildren, are highly sensitive to certain bitter flavors associated withoat products high in oat bran. Also, in certain markets, especiallyEuropean RTE cereal markets (excluding the British Isles where oat mealis commonly consumed), oat based consumer food products are unfamiliarin taste and such low oat bran/low oat flavor RTE cereal products mayfind particular appeal. Notwithstanding the lower levels all of β-glucanin the low bran oat flour 40, the low bran oat flour 40 nonethelessprovides high levels of protein.

The low bran oat flour 40 is characterized by a low level of β-glucan.The low bran oat flour 40 has a β-glucan content of less than 3%,preferably less than 2% β-glucan, and in the most preferred embodimentscomprises less than 1% β-glucan. In certain preferred embodiments, thelow bran oat flour 40 has a β-glucan content of no greater than 50% ofthe native level in the oat flour 19 and in more preferred embodimentsno greater than 25% of the native β-glucan level of the oat groats 15 oroat flour 19 starting material.

In even more preferred embodiments, the low bran oat flour 40 not onlyis characterized by low levels of β-glucan but also by higher flavorlevels although not of the bitter notes from the bran fraction. In thosevariations in which the cleaned conditioned oat groats 17B are providedby practicing the heat conditioned step 16B according to the teaching'109 patent, the low bran oat flour 40 can be characterized by asyringic it to ferulic acid ratio of greater than or equal to 2.5, thatis, a ratio of the HPLC (High Performance Liquid Chromatography)syringic acid peak to ferulic acid peak, of about ≧2.5 which ratio ischaracteristic of a toasted flavor attribute. Also, the low bran oatflour 40 can exhibit improved cooking characteristics that can be andexpressed as having a Farinograph value of between 5 and 20 minutes. Asresult, as noted above, the low bran oat flour 40 can be used to providean improved puffed ready eat cereal that appeals not only to those oatsensitive adult consumers but also for children. As result, the puffedready-to-eat cereal finds particular suitability for use in theprovision of an “all-family” oat based puffed ready eat cereal. Whilesuch puffed ready to-eat oat cereals can include a sugarcoating, it isan advantage of the present invention that such puffed oat based readyeat cereals require lower levels of a topical sugarcoating to offset anyundesirable bitter oat flavor notes that hereto for resulted from theoat flour cereal ingredient. Moreover, for those consumers that find theflavor of oat-based ready eat cereals less familiar (such as in certainEuropean countries where oat consumption by people is less common) suchan advantage provides the opportunity to provide the nutrition andhealth benefits of oat based food products to these consumers in a moreappealing form.

The low bran oat flour 40 by virtue of its low bran content exhibits anappealing light color and texture. Consequently, the present low branoat flour 40 presents increased appeal as an ingredient for nonfoodproducts especially as a high-quality ingredient for cosmetics such asskin creams or soap products comprising oat materials.

The high β-glucan oat bran product 50 of the present inventioncomprising about 8% to 9% β-glucan finds used as a high-value specialtyfood ingredient that can be added to a wide variety of food products toincrease the β-glucan content or can be used as an ingredient in theprovision of a hot cooked cereal (in like manner as described above foroat bran fraction 28). It will be appreciated that the present drymilling and extraction methods 10 of the present invention provide aneconomical process for the extraction and provision of β-glucan fromcommodity oats. At present, it is expected that this ingredient will bepriced at a premium of about 300% per pound or kg compared to the priceof oat groats.

The finished oat bran 50 material of the present invention has β-glucancontent concentration that is higher than the starting or native levelof the oat flour 19 from which it is extracted. This improvement can beexpresses as a ratio of final to initial concentrations sometimesreferred to as a beneficiation ratio (% final/% initial). The presentmethods provide beneficiation ratios ranging from about 1.01 to about2.75, preferably at least 1.5 (i.e., at least 150% of the native level)to about 2.25 and for best results at least 2.0 (i.e., at least 200% ofthe native level). Yields as high as 38% can be realized when lowerbeneficiation is accepted. At lower yields, oat bran materials having atmuch as 275% of the native level can be realized.

In one embodiment of the present invention, the high β-glucan oat bran50 can be combined with an oat flour such as the whole grain oat flour19 and blended in step 70 to provide a soluble fiber enriched highβ-glucan oat flour 80. By blending various amounts of the high β-glucanoat bran 50 with the oat flour 19, a high β-glucan oat flour 80 can beformulated having a higher level of β-glucan than its native level, thatis oat flour 80 will have a β-glucan content ranging from about 4-7%,i.e., more typical of that of oat bran rather than oat flour. The oatflour 19 and the high β-glucan oat bran 50 can be combined in anydesired weight ratio ranging from about 100:1 to about 1:10, preferablyfrom about 100:10 to about 100:50, and for best results about 100:30.For example, in a particular execution, the oat bran 28 and/or 50 isadded oat flour 19, whether or not subjected to oat flour milling step76, to provide an enriched (in β-glucan) oat flour be in a weight ratiowith oat bran 50 in a weight ratio ranging from about 1:1 to about 2:1,preferably about 4:1 to about 2:1 and for best results about 3:1 oatflour to oat bran(s) (28 and/or 50). The oat flour 19 can be aconventional whole grain oat flour. However, and in more preferredembodiments, the oat flour 19 is prepared to according to the methods ofthe '109 patent. By virtue of the improved flavor profile as taught inthe '109 patent, and especially in those embodiments of the presentinvention in which the cleaned conditioned oat groats 17 are likewiseprepared according to the teaching '109 patent, the high to β-glucan oatflour 80 of the present invention is characterized not only by higherlevels all of β-glucan but also by improved flavor and cookedcharacteristics. In certain variations, the methods can includesupplemental milling 76 the coarse oat flour 19 to provide a fine milledoat flour 19A in full or partial substitution for the coarse milled oatflour 19.

The high β-glucan oat flour 80 finds particular suitability for use inthe provision of oat based food ingredients characterized by high levelsall of desirable β-glucan soluble fiber, especially in the provision ofpuffed cooked cereal dough oat ready-to-eat cereal products. Such highβ-glucan, high soluble fiber puffed oat based cooked cereal ready eatcereal products fine particular appeal to those consumers desiring thehealth the nutrition benefits associated with consumption of oat basedfoods.

Referring again to FIG. 1, it can be seen that the oat flour 80 can becombined with water and other cereal ingredients (e.g., salt(s), sugar,starch). In preferred embodiments, the present whole grain oat flourcomprises 80%>of the dough (dry weight basis). The cooked cereal dough28 can have a moisture content of about 12 to 35%. The present methodscan further comprise a cooking step 90 for forming a cooked cereal dough92 having high levels of β-glucan (i.e., higher than 4%). The methodscan additionally comprise the step of forming 100 the cooked cerealdough into a finished R-T-E cereal 110 having high levels of β-glucan(i.e., higher than 4%. For example, the cooked cereal dough can beformed into partially dried “O” shaped pellets and puffed to formimproved puffed “O” shaped finished dried (5% or less moisture) RTEcereal pieces or can be formed into flakes, biscuits, squares, shreds orother common RTE cereal shapes. If desired, both the cooking, doughforming and puffing steps can be practiced in a single pieces ofequipment such as in a twin screw extruder or can be practiced in two ormore separate equipment operations.

In the more preferred form, such puffed oat based cooked cereal doughready-eat-cereal products of the present invention have a densityranging from about 0.1 to about 0.35 g/cc as well as a p-glucan contenthigher than 4%, preferably about 4-7%. Such products, if desired, caninclude a topical sweetener coating.

Also, if desired, such products can be additionally fortified withsupplemental soluble fiber ingredients such as inulin to provideproducts characterized by even higher levels all soluble fiber. Thesupplemental soluble fiber ingredient such as inulin can be includedinto the cooked cereal dough from which the puffed ready-to-eat cookedcereal dough product is prepared or can being provided, in whole or inpart, in the topical sweetener or sugar coating. The high β-glucancontent puffed oat ready-to eat cereal product can be in the form of and“O's” (rings or toroid), puffed spheres or other ovoids or roundedshapes, letters, figurines, geometric shapes, and combinations thereof.In still other variations, the high β-glucan oat flour 80 can be used toprepare a cooked cereal dough oat based ready eat dried cereal productsin the form of flakes, shreds, biscuits, or other forms of dried cookedcereal products.

In still other variations, the dried puffed ready-to-eat cereal productsof the present invention can be combined with a binder such as aconcentrated sugar syrup to provide formed products such as bars. Instill other variations, the high β-glucan oat flour 80 can be used as aminor ingredient in the provision of aggregates or agglomerates such asprepared by sugar panning for addition to overriding ready to eat cerealproducts in other consumer food products. In still other variations, thehigh β-glucan oat flour 80 can be used as a supplemental ingredient toprovide nutrition. For example, the ingredient can be used to fortifythe soluble fiber level of various bread products or to provide an oatflavored leavened and baked bread item.

Is still other variations, the high β-glucan oat bran 50 can be sold asa hot cereal for human consumption. In still other variations, theflaked oat bran 25 or oat bran 28 or 31 prepared by the presentinvention finds suitability for use as a hot cereal ingredient providingnot only relatively high levels all of β-glucan but also is in the formconvenient for the rapid preparation of 80 high oatmeal type product forhuman consumption. In still other variations, the flaked oat bran 25 canbe combined with the oat bran 50 in various ratios.

The present preferred oat ingredients have minimal peroxidase activityand a ratio of the HPLC syringic acid peak to ferulic acid peak, ofabout >2.5 which ratio is characteristic of a toasted flavor attribute.

The preferred whole grain oat flour 80 can also be characterized in partby a Farinograph cook time value ranging from about 5 to 20 minutesindicating at least partial cooking. The conditioned oat flour has aFarinograph cook or development time value of about 5 to 20 minutesindicating partial gelatinization or partial precooking. The at leastpartially cooked high β-glucan content oat flour 80 desirably reducesthe duration of the cook step 90 to provide a cooked cereal dough.

For example, in one preferred embodiment, conventional extended cooktime cereal cookers are employed to prepare the cooked cereal dough. Inthis embodiment, cook times can range from about 30 to 70 minutes at 200to 230° F. (93 to 110° C.) representing a 5 to 15% reduction in cooktimes compared to conventional processing. Notwithstanding the reducedcook times, the oat based cooked cereal doughs 28 are characterized bythe desired cooked flavor characteristic of an extended cooked cerealdough.

In another embodiment, the oat flour 80 is combined with minor amountsof the other R-T-E cereal ingredients and water and cooked in a shorttime cooker extruder, whether a single screw or twin screw extruder, forabout 0.5 to eight minutes and mechanically worked to form the cookedcereal dough 28. The dough can optionally include a variety of starchesor other farinaceous materials. In one variation of this embodiment, thecooked cereal dough 28 is similarly processed as described above toproduce either an oat flaked product or a puffed oat product, includinga toasted puffed oat product. The cooked dough can be fed to a pelletformer or the cooker extruder can be equipped with a pellet forming diehead to form pellets which are fed directly to the pellet dryer.

In another variation, the cooked cereal dough 28 is extruded underconditions of temperature and pressure and through appropriately shapedand sized dies so as to cause an immediate expansion or puffing of thecooked cereal dough upon extruding to ambient conditions or “directlyexpanded.” The directly expanded puffed oat cooked cereal dough is thenface cut to form individual pieces 49. The puffed pieces can be anysuitable size and shape such as letters or as ring shaped pieces. Theindividual puffed cereal pieces 49 can optionally be toasted to impart adesirable further developed toasted oat flavor to the puffed pieces 48whether by radiant heating, hot air and/or high intensity microwaveheating. It is a surprising advantage that the present oat flours can beused to produce by direct expansion high oat flour puffed cooked cerealdough pieces 49 having a high toasted grain flavor especially at highoat flour concentration (i.e., 50-95% oat flour, dry weight basis,preferably about 80-95%). Thereafter, the oat puffed pieces or flakes,whether dried or toasted to 2 to 6% moisture, can be directly packaged56 for sale to consumers.

It has been previously known that oat material containing cooked cerealdoughs can be directly expanded. However, the doughs in prior knownmethods suffered from one or more deficiencies including using oat flouringredients that are defatted, or high levels of starch, or lack ofcooked grain flavor, or had an undesirable texture due to overworkingthe cereal dough in the cooker extruder.

In another variation, the oat pieces, whether puffed 45 or flaked 47and/or toasted, can be presweetened by topically adding a sugar syrupsweetener composition 42. In this embodiment, the cereal pieces orcereal base, (45, 47) can be charged to an enrober 48 and the sugarsyrup 42 heated in heater 46 is topically applied thereto. The enrobingtumbling action is continued for a few ‘minutes to ’ evenly coat thecereal base (45, 47). If desired, various particulates such as nutpieces, fruit bit pieces, bran, or other topical additives (not shown)can be added to the enrober 48. A vitamin solution 44 optionally canalso be added to the cereal base such as by adding to enrober 48 such asby in line admixing with the heated sugar syrup 42 or by separatelyspraying in the enrober 48. The coated cereal base 49 whether puffed,flaked, shredded, biscuit, shredded biscuit, cut dough sheet pieces, orother forms is then dried in dryer 50 to a final moisture content ofabout 2 to 5% to remove the added moisture associated with the sugarsyrup 44 to form a presweetened finished R-T-E cereal 53. The finishedcereal 53 is then conventionally packaged 56 for distribution and saleto customers.

The oat flour development time (or “Cook Times”) values are measuredusing the following equipment and procedures. A dough made of oat flourand water is developed and cooked at 95° C. in a Brabender Do-corder(Brabender Do-corder type PL-V340 or equivalent equipped with a type2-16-000 mixer/measuring head blade speed ratio/drive-to-driven:3.2)with sigma type blades (type SB). The Do-corder is colloquially referredto by cereal chemists as a Farinograph. The changes in the oat doughrheological properties that occur during the analysis reflect therelative energy required to form a cohesive dough with the particularoat flour sample recorded on the Do-corder chart provide a functionalityfinger-print.

Cooking Characteristics measurement—Farinograph: A 60 gram oat floursample is transferred to the measuring head/mixing bowl. The bowltemperature is 95° C. and the two paddles inside the bowl are rotating,with the test speed set at 100 rpm. A block, with a port for theaddition of water, is placed in the opening of the mixing bowl toprevent the evaporative loss of the moisture in the flour. The chart penrecording the resistance on the rotating paddles as a function of testtime is set to the baseline (0 Consistency Units). The flour is given150 seconds to heat. At the end of the 150 seconds, 25 milliliters ofwater is added through the port in the mixing bowl block. As an oatdough begins to form, the chart pen raises off the baseline to a heightof 400 to 600 Consistency Units. An initial mixing peak viscosity isobtained within one minute of the addition of the water. After reachinga peak, the viscosity gradually declines for the next three to 15minutes and reaches a minimum of 250 to 350 Consistency Units (TheTrough Viscosity). At this point the dough viscosity begins to increase.At eight to 25 minutes into the analysis, the viscosity will peak at 380to 420 Consistency Units and begin to decline. The test is concluded atthis point. The Farinograph plot from the chart recorder will show twopeaks. The first peak is the mixing peak and the second peak is thedevelopment peak. The Cook Time or development time as used herein isdefined as the time point at which the increasing dough consistencyportion of the development peak first reaches the dough consistencyplateau value, or more simplistically, when the second viscosityincrease ceases. The cook time decreases with increased degree ofpretreatment. (Less than 15 minutes, higher level of pretreatment; 15 to22 minutes, moderate level of pretreatment; greater than 22 minutes, lowlevel of pretreatment).

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

1. A high β-glucan oat based cereal food product fabricated from acooked cereal dough made from oat flour and oat bran comprising: a highβ-glucan content oat flour, comprising a blend of: A. a milled whole oatflour having 1) a native β-glucan content, 2) a Farinograph value ofabout 5 to 20 minutes, 3) a ratio of syringic acid peak to ferulic acidof greater than or equal to 2.5, and 4) a negative peroxidase activity;and, B. a high β-glucan oat bran having 1) a β-glucan content of 7% orgreater; 2) a Farinograph value of about five to 20 minutes; 3) a ratioof syringic acid peak to ferulic acid peak of greater than or equal to2.5; and, 4) a negative peroxidase activity.
 2. A high β-glucan oat branhaving a β-glucan content of 7% or greater; a Farinograph value of aboutfive to 20 minutes; a ratio of syringic acid peak to ferulic acid peakof greater than or equal to 2.5; and, a negative peroxidase activity. 3.The high β-glucan oat bran of claim 2 having a β-glucan content of 8% orgreater.
 4. The high β-glucan oat bran of claim 3 having a particle sizeof greater than 300 μm.
 5. The high β-glucan oat bran of claim 4 havinga β-glucan content of about 8.5%.
 6. The high β-glucan oat bran of claim2 admixed with flavoring levels of sweeteners(s) and salt.
 7. A highβ-glucan content oat flour, comprising a blend of: A. milled whole oatflour having a native β-glucan content 1) a Farinograph value of about 5to 20 minutes, 2) a ratio of syringic acid peak to ferulic acid ofgreater than 2.5, and 3) a negative peroxidase activity; and, B. highβ-glucan oat bran having a β-glucan content of greater than 7%.
 8. Theoat flour of claim 7 having a weight ratio of milled whole oat flour tohigh β-glucan oat bran ranging from about 1:1 to about 2:1.
 9. The oatflour of claim 8 having a Farinograph value of about 6 to 14 minutes,and a ratio of syringic acid peak to ferulic acid peak of >3.5.
 10. Theoat flour of claim 9 having a weight ratio of milled whole oat flour tohigh β-glucan oat bran ranging from about 4:1 to about 2:1.
 11. The oatflour of claim 10 having a weight ratio of milled whole oat flour tohigh β-glucan oat bran of about 3:1.
 12. A high β-glucan oat basedcereal food product fabricated from a cooked cereal dough comprising anoat bran having a β-glucan content greater than 7%.
 13. The food productof claim 12 in the form of a ready-to-eat cereal.
 14. The food productof claim 13 wherein the ready to eat cereal is in the form of piecesselected from the group consisting of puffs, flakes, shreds, biscuitsand mixtures thereof.
 15. The food product of claim 14 wherein the puffsare in the form of sphere, ovoid, letter, figurine, geometric shapes,rings, and mixtures thereof.
 16. The food product of claim 12 in theform of a loose mixture.
 17. The food product of claim 14 in the form ofa bar fabricated from a quantity of pieces bound by a binder.
 18. Thefood product of claim 15 wherein at least a major portion are in theform of ring shaped pieces.
 19. The food product of claim 12 wherein thefood pieces are fortified with inulin.
 20. The food product of claim 19wherein at least a portion of the inulin is in the form of a topicalcoating.
 21. The food product of claim 14 in the form of flakes.
 22. Thefood product of claim 12 in the form of a leavened and baked bread.